diff --git a/wadsrc/static/shaders/glsl/material_pbr.fp b/wadsrc/static/shaders/glsl/material_pbr.fp
index 5212177e1..895b6183b 100644
--- a/wadsrc/static/shaders/glsl/material_pbr.fp
+++ b/wadsrc/static/shaders/glsl/material_pbr.fp
@@ -181,7 +181,7 @@ vec3 ProcessMaterial(vec3 albedo, vec3 ambientLight)
 	//vec3 ambient = (kD * diffuse + specular) * ao;
 	vec3 ambient = (kD * diffuse) * ao;
 
-	vec3 color = ambient + Lo;
+	vec3 color = max(ambient + Lo, vec3(0.0));
 
 	// Tonemap (reinhard) and apply sRGB gamma
 	//color = color / (color + vec3(1.0));